(1) Field of the Invention
This invention relates to methods of filling contact holes in dielectric layers with conducting metal plugs and more specifically to methods of using chemical vapor deposition of titanium suicide to form conducting metal plugs.
(2) Description of the Related Art
Contact holes in dielectric layers formed on integrated circuit wafers are typically filled by forming layers of titanium and titanium nitride using sequential sputtering forming layers of titanium and titanium nitride on the sidewalls and bottoms of the via holes. The wafer is then thermally processed to form titanium silicide at those points where the titanium is in contact with silicon. A blanket deposition of tungsten or other metal is then used to fill the contact holes.
U.S. Pat. No. 5,534,730 to Mori et al. describes contact holes with thin oxide at the bottom. Titanium silicide, TiSi.sub.x, is deposited in the contact hole using chemical vapor deposition. As the TiSi.sub.x film is formed the oxide is reduced and the titanium silicide forms a conductive contact to the silicon below the oxide.
U.S. Pat. No. 5,376,405 to Doan et al. describes a method of using chemical vapor deposition for depositing titanium silicide on a an integrated circuit wafer.
U.S. Pat. No. 5,066,612 to Ohba et al. describes the use of multilayer insulating layers for activating selective metal growth in filling contact holes with metal.
This invention describes methods of filling contact holes in dielectric layers formed on an integrated circuit wafer using chemical vapor deposition of titanium silicide.